diff --git a/sys/dev/rge/if_rge.c b/sys/dev/rge/if_rge.c
--- a/sys/dev/rge/if_rge.c
+++ b/sys/dev/rge/if_rge.c
@@ -959,29 +959,24 @@
 	case SIOCSIFFLAGS:
 		RGE_LOCK(sc);
 		if ((if_getflags(ifp) & IFF_UP) != 0) {
-			if ((if_getdrvflags(ifp) & IFF_DRV_RUNNING) == 0) {
-				/*
-				 * TODO: handle promisc/iffmulti changing
-				 * without reprogramming everything.
-				 */
+			if ((if_getdrvflags(ifp) & IFF_DRV_RUNNING) != 0) {
+				if (((if_getflags(ifp) ^ sc->rge_if_flags)
+				    & (IFF_PROMISC | IFF_ALLMULTI)) != 0)
+					rge_iff_locked(sc);
+			} else
 				rge_init_locked(sc);
-			} else {
-				/* Reinit promisc/multi just in case */
-				rge_iff_locked(sc);
-			}
 		} else {
-			if ((if_getdrvflags(ifp) & IFF_DRV_RUNNING) != 0) {
+			if ((if_getdrvflags(ifp) & IFF_DRV_RUNNING) != 0)
 				rge_stop_locked(sc);
-			}
 		}
+		sc->rge_if_flags = if_getflags(ifp);
 		RGE_UNLOCK(sc);
 		break;
 	case SIOCADDMULTI:
 	case SIOCDELMULTI:
 		RGE_LOCK(sc);
-		if ((if_getflags(ifp) & IFF_DRV_RUNNING) != 0) {
+		if ((if_getflags(ifp) & IFF_DRV_RUNNING) != 0)
 			rge_iff_locked(sc);
-		}
 		RGE_UNLOCK(sc);
 		break;
 	case SIOCGIFMEDIA:
diff --git a/sys/dev/rge/if_rgevar.h b/sys/dev/rge/if_rgevar.h
--- a/sys/dev/rge/if_rgevar.h
+++ b/sys/dev/rge/if_rgevar.h
@@ -200,6 +200,8 @@
 #define RGE_IMTYPE_SIM		1
 	int			sc_watchdog;
 
+	int			rge_if_flags;
+
 	uint32_t		sc_debug;
 
 	struct rge_drv_stats	sc_drv_stats;